Reservoir module comprising a piston rod

ABSTRACT

A product dispensing apparatus including a reservoir module, a dosing module and a dose setting member. The reservoir module includes a front casing section, a block, a first connector, a piston, and a piston rod moveable in a dispensing movement and against the dispensing movement, and including a return block engageable with the block, wherein engagement between the block and the return block prevents the piston rod from moving against the dispensing movement. The dosing module includes a rear casing section, including a second connector which is engageable with the first connector to form a detachable connection between the reservoir module and the dosing module, and a dosing and drive device. The dose setting member engages the piston rod such that it is moveable together with and in the same direction as the piston rod during the dispensing movement and is moveable relative to the piston rod against the dispensing movement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CH02/00411, filed on Jul. 22, 2002, which claims priority to GermanApplication No. 201 12 501.3, filed on Jul. 30, 2001 and GermanApplication No. 101 63 327.0, filed on Dec. 21, 2001, the contents ofboth of which are incorporated herein in their entirety by reference.

BACKGROUND

The invention relates to administering devices, including injectiondevices, and methods of their operation and use. More particularly, itrelates to a reservoir module which has an associated piston rod, and adispensing or administering apparatus comprising such a reservoirmodule.

In a preferred embodiment, the product dispensing or administeringapparatus is an injection apparatus or inhalation apparatus for medical,therapeutic, diagnostic, pharmaceutical or cosmetic applications. Onepreferred example of injection apparatus is injection pens, inparticular semi-disposable pens.

WO 97/17095 describes an injection apparatus consisting of a dosing andactivating module and a reservoir module which are detachably connectedto each other. The reservoir module is designed as a disposable module,while the dosing and activating module is intended to be re-used—oncethe reservoir module has been used up or emptied—with a new reservoirmodule. The reservoir module contains a reservoir for a product to beinjected and mounts a piston rod which acts on a piston accommodated inthe reservoir to deliver product. The piston rod comprises an outerthread which is in threaded engagement with an inner thread of a dosingsetting member. The piston rod is linearly guided, such that when thedosing setting member is rotated, the piston rod is moved towards thepiston and a slight distance between a front end of the piston rod andthe piston is thus changed. The reservoir module also mounts the dosingsetting member and thus comprises the piston rod and the dosing settingmember, which are disposed of together with the reservoir as a singlemodule, after the reservoir as been emptied.

An advantage of the design of such semi-disposable injection apparatusis that the parts of the injection apparatus involved in dosing anddelivery only have to be configured for delivering the contents of asingle reservoir. This reduces the price of these parts. Since, ifrepeatedly used, such parts would always have to be guided back again toan initial position by the user, they would furthermore be exposed to arisk of damage which should not be underestimated. The reliability ofcorrectly selecting and delivering the dosage need not therefore be lessfor semi-disposable injection apparatus than for completely re-usableapparatus. Moreover, exchanging a complete reservoir module is simplerthan exchanging only a reservoir.

The dosage setting member of the known apparatus is pushed into a rearposition, in which the product is dosed, by a pressure spring which issupported by a casing of the reservoir module. By dosing the product,the piston rod is advanced towards the piston relative to the dosagesetting member and the casing of the reservoir module. The product isdelivered by means of a dosing and activating device which is mounted ina casing of the dosing and activating module and pushes against a rearabutting area of the dosage setting member. The dosing and activatingdevice pushes the dosage setting member, and due to the threadedengagement also the piston rod together with it, in the advancingdirection.

SUMMARY

It is an object of the invention to provide a dose administering ordispensing apparatus, in particular injection apparatus, using areservoir module which has an associated piston rod, while maintainingreliability with respect to correctly selecting and delivering a dose.

It is an object of the invention to further reduce the price ofadministering or dispensing apparatus, in particular injectionapparatus, using a reservoir module which serves as a piston rod mountor carrier, while maintaining reliability with respect to correctlyselecting and delivering a product dosage.

The invention relates to product dispensing apparatus, in someembodiments injection apparatus, comprising a reservoir module and adosing and activating module, which are detachably connected to eachother.

In one embodiment, the present invention comprises a dispensingapparatus comprising a reservoir module comprising a front casingsection, a block, a first connector, a piston, and a piston rod moveablein and against a dispensing movement and including a return blockengageable with the block, wherein engagement between the block and thereturn block prevents the piston rod from moving against the dispensingmovement, a dosing module comprising a rear casing section including asecond connector engageable with the first connector to form adetachable connection between the reservoir module and the dosingmodule, and a dose setting member engageable with the piston rod suchthat it is moveable together with and in the same direction as thepiston rod during the dispensing movement and is moveable relative tothe piston rod against the dispensing movement.

In some embodiments, the product dispensing apparatus is preferablyalready formed by two modules alone, the reservoir module and the dosingmodule, which carry the operating components or operating mechanisms.The reservoir module comprises a front casing section of the productdispensing apparatus, comprising a reservoir for a product to bedelivered, which is preferably fluidic and can be injected, and a firstconnecting means. A piston is accommodated in the reservoir, such thatproduct is delivered from the reservoir by shifting the piston in anadvancing direction. The reservoir module further comprises a piston rodwhich is held by the front casing section. Lastly, the reservoir modulecan comprise an injection needle, or a nozzle for needle-freeinjections.

The reservoir can be formed by a container which is accommodated by thecasing. For example, an ampoule can form the reservoir. In principle,however, the reservoir can also be formed by the casing itself, i.e.,without interposing a product container. The product to be injected oradministered is preferably a liquid for medical, therapeutic,diagnostic, pharmaceutical or cosmetic applications, for example insulinor a growth hormone. In some embodiments, the product dispensingapparatus is preferably an injection apparatus and is preferablyemployed in applications in which a user self-administers the producthim/herself, as is common in diabetes therapy. However, its use in thefield of in-patients or out-patients, by trained staff, is not to beexcluded. In other applications or uses, in which it is necessary ordesirable to dispense a product in doses, the product can be a paste.

The piston rod can be connected fixedly, i.e., permanently, to thepiston, by which forming or integrating the piston and piston rod as onepiece is also to be understood. In a preferred embodiment, however, thepiston and the piston rod are embodied as separate components, and afront end of the piston rod pushes against a rear side of the piston forthe purpose of delivering product.

The dosing and activating, or actuating, module comprises a rear casingsection of the product dispensing apparatus, comprising a secondconnecting means which together with the first connecting means formsthe detachable connection between the reservoir module and the dosingand activating module. In some embodiments, the front casing section andthe rear casing section preferably form the whole casing of theapparatus. The first and second connecting means can, for example, takethe form of a rotational connection, in particular a screw connection.In some preferred embodiments, the two casing sections are linearly slidonto each other, wherein the first connecting means and the secondconnecting means form a linear guide which prevents the two casingsections from rotating relative to each other. Furthermore, theypreferably form a latching means together, such that the regions of thecasing sections slid over each other cannot simply be pulled apartagain.

The dosing and activating module further comprises a dosing and driveelement for providing or performing a dosing movement for selecting aproduct dosage and a delivery movement for delivering the productdosage. Such movements may be performed relative to the connected casingsections.

If the connecting means form a latching means, in some embodiments, thelatching means preferably comprises a latching block which only allowsthe two casing sections to be latched or connected to each other in afront end position of a drive element or the dosing and drive element ofthe dosing and drive device.

In some embodiments, the product dispensing apparatus comprises a dosagesetting member which is moved in the advancing direction by the dosingand drive device during the delivery movement, and which engages witheach of the piston rod and at least one of the casing sections such thatit can only be moved jointly with the piston rod in the advancingdirection and is moved counter to the advancing direction, relative tothe piston rod, by the dosing movement of the dosing and drive device.In some embodiments, the engagement with the piston rod is preferably athreaded engagement. In principle, however, the engagement can also beformed differently, for example as a toothed engagement which allows thedosage setting member to move counter to the advancing directionrelative to the piston rod, but prevents the dosage setting member frommoving in the advancing direction relative to the piston rod. While thedosage setting member can in principle be a component of the dosing andactivating module, it is, in some embodiments, a component of or coupledto the reservoir module, i.e., it is preferably already held on thereservoir module before the reservoir module is connected to the dosingand activating module.

In accordance with the invention, the front casing section comprises ablocking means and the piston rod comprises a returning blocking means,which are in blocking engagement with each other, the blockingengagement allowing the piston rod to move in the advancing directionrelative to the front casing section, but preventing this counter to theadvancing direction. As a desired side effect, the blocking engagementalone can ensure that the piston rod is not moved in the advancingdirection relative to the front casing section while the product dosageis being selected. If the piston rod is not yet fixed sufficientlysecurely for this purpose by the blocking engagement alone, the blockingmeans also comprises a braking means in order to prevent the piston rodfrom moving in the advancing direction while the product dosage is beingselected, by exerting an additional frictional force.

In the product dispensing apparatus of the invention, as compared to theapparatus of WO 97/17095, a pressure spring is eliminated, which in theknown apparatus ensures that the piston rod and the dosage settingmember assume their rearmost position during the dosing process. Savingon parts simultaneously means saving on costs. The saving effect isaugmented by the fact that the reduction in the number of parts isregistered on the side of the reservoir module. Since, in someembodiments, the reservoir module in accordance with the invention ispreferably designed as a disposable module, the saving effect makesitself felt every time such a reservoir module is exchanged.

In embodiments in which the dosage setting member participates in thedosing movement of the dosing and drive device, it is preferablyensured—when establishing the coupling between the dosing and drivedevice and the dosage setting member necessary for this, brought aboutby connecting the two modules—that a dosing movement of the dosagesetting member cannot occur. For this purpose, the dosage setting memberand the dosing element or combined dosing and drive element of thedosing and drive device, to be coupled to the dosage setting member, areheld with respect to each other in pre-set positions with respect to thedosing movement when connecting the modules. If the dosing movement is arotational movement about a rotational axis pointing in the direction ofthe delivery movement, the dosage setting member and the dosing elementor dosing and drive element are held with respect to each other inpre-set rotational angular positions, when connecting the modules. Ifthe dosage setting member and the dosing element or dosing and driveelement are held by the front casing section and rear casing section,respectively, in a pre-set rotational angular position, then the citedlinear guide of the casing sections can advantageously ensure thatestablishing the coupling does not cause a dosing movement of the dosagesetting member. If the casing sections perform a rotational movementrelative to each other when the modules are connected, a dosing movementof the dosage setting member is prevented another way.

The product dispensing apparatus can comprise a block which ensures thatthe reservoir module can only be detached from the dosing and activatingmodule in a foremost position of the piston rod. In order to reliablyprevent the reservoir module from being used again, it is necessary inthis case to hold the piston rod in its foremost position, such that theuser cannot transfer it back to an axial position in which, once thereservoir has been exchanged, product can be delivered again using thesame piston rod. In some preferred embodiments, the blocking engagementbetween the returning blocking means formed on the piston rod and theblocking means of the front casing section hold the piston rod aftereach individual delivery of a product dosage, such that it is preventedfrom being transferred to an earlier axial position. If it is furtherensured that the piston rod and the reservoir cannot be separated fromeach other, the reservoir is advantageously prevented from beingexchanged in all axial positions of the piston rod. The blockingengagement thus also simultaneously forms a securing engagement in anyaxial position of the piston rod.

In preferred exemplary embodiments, the returning blocking means isformed by serrated teeth which project from the piston rod and form arow of teeth having a preferably regular separation. The presentinvention has recognized that the principle of the toothed rack, knownin its own right for dosing, can be advantageously employed in areservoir module designed as a disposable module, in order to lower thecosts for the reservoir module and as a result especially also for theproduct dispensing system as a whole. A row of serrated teeth,comprising teeth tapered in the advancing direction and rear blockingareas, also simultaneously provides, as a by-product in each blockingengagement, the securing engagement which prevents the piston rod fromreturning.

The securing engagement between the blocking means and the piston rod,which prevents the piston rod from returning, is non-releasable. In thiscontext, non-releasable means that it cannot be released by the userwithout being destroyed. However, it should not be ruled out that thereservoir module can be reprocessed into a closed cycle and that theblocking engagement can in this case be released, for example by themanufacturer by means of special tools. It is, however, ensured that auser who is using the product dispensing apparatus forself-administering, for example for administering insulin or growthhormones, cannot exchange or re-fill the reservoir.

The dosing and drive device of the present invention may operatemanually, semi-automatically or fully automatically. In the first case,both the rotational dosing movement and the translational deliverymovement are performed manually. In the second case, either therotational dosing movement or the translational delivery movement isperformed manually and the other movement is performed using motors orby means of another type of force application, for example by means of aspring force, when the user has triggered the corresponding movementusing an activating handle or other suitable actuator. In the thirdcase, that of the fully automatic dosing and drive device, the dosingmovement and the delivery movement are performed using motors or bymeans of another force, for example a spring force. In this case, onlythe dosage is selected manually, for example by means of one or morebuttons, and the delivery movement is likewise triggered by the userusing a corresponding activating handle of its own. In most embodiments,the administering apparatus in accordance with the invention is equippedwith a manual dosing and drive device, which is then referred to as adosing and activating device. Thus, whenever a dosing and activatingdevice is mentioned, it is therefore the manual embodiment which isbeing referred to. Where a dosing and drive device is mentioned, this isnot intended to restrict the invention with respect to being manual,semi-automatic or fully automatic, but rather to comprise each of theseembodiments. The term “dosing and activating module” is, however, usedin connection with all the embodiments of the dosing and drive device.

The dosing and drive device can separately comprise a dosing elementwhich performs the dosing movement and a drive element which performsthe delivery movement. In some preferred embodiments, however, thedosing movement and the delivery movement are performed by the same bodyof the dosing and drive device which is therefore also referred to inthe following as a dosing and drive element or dosing and activatingelement.

The present invention may be used to deliver or administer any suitablesubstance or product, including a fluid or a liquid such as those havinga medical, therapeutic, diagnostic, pharmaceutical or cosmeticapplication. The product can for example be insulin, a growth hormone,or a thin or thick, pulpy food. The administering apparatus may beemployed in applications in which a user self-administers tohim/herself, as is common in diabetes therapy, however, its use in thefield of in-patients or out-patients, by trained staff is not to beexcluded.

In the case of an injection apparatus, the product can be administeredby means of an injection cannula or a nozzle for needle-free injections.The product can be injected or infused subcutaneously or venously, oralso intramuscularly. When administered by inhalation, the selectedproduct dosage can be delivered from the reservoir into a chamber of theinhalation apparatus and vaporized for inhalation by means of avaporizing means. Furthermore, oral ingestion is conceivable, oradministering via the esophagus, to name but a few administeringexamples.

In some embodiments, the administering apparatus is preferablysemi-disposable. In this case, the front casing section is a support fora reservoir module which is disposed of or recycled once the reservoirhas been emptied, and the rear casing section is a support for a dosingand activating module which can be repeatedly used in conjunction with anew reservoir module. Since the reservoir module can also be treatedseparately as a disposable module, it is also a separate subject of theinvention. The dosing and activating module can also be also a separatesubject of the invention. Equally, a system consisting of anadministering apparatus and at least one reservoir module, which canreplace the reservoir module of the apparatus once it has been used,forms a subject of the invention. The duplex design of the administeringapparatus, divided into a portion provided for use only once and aportion provided for repeated use (semi-disposable), is advantageous forinjection pens in particular, but also for example for inhalationapparatus or apparatus for orally ingesting a product or for artificialfeeding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts two portions of a reservoir module in accordance with afirst exemplary embodiment;

FIG. 2 depicts the reservoir module obtained from the two portions ofFIG. 1;

FIG. 3 depicts an injection apparatus comprising the reservoir module ofFIG. 2, in accordance with the first exemplary embodiment, in alongitudinal section;

FIG. 4 depicts a portion of the injection apparatus of FIG. 3;

FIG. 5 depicts a mechanism holder of the reservoir module, in alongitudinal section and two views;

FIG. 6 depicts a blocking means for a piston rod, mounted by themechanism holder;

FIG. 7 depicts a piston rod in a longitudinal section and a front view;

FIG. 8 depicts a latching block in a longitudinal section, a view and atop view;

FIG. 9 depicts a second exemplary embodiment of an injection apparatus;

FIG. 10 depicts the cross-section A-A of FIG. 9;

FIG. 11 is the cross-section B-B of FIG. 9;

FIG. 12 is the cross-section C-C of FIG. 9;

FIG. 13 is the cross-section D-D of FIG. 9;

FIG. 14 depicts the mechanism holder of the second embodiment, in aperspective representation;

FIG. 15 depicts the mechanism holder of FIG. 14;

FIG. 16 is the cross-section A-A of FIG. 15;

FIG. 17 depicts the dosage setting member of the second embodiment, in aperspective representation;

FIG. 18 depicts the dosage setting member of FIG. 17, in a longitudinalsection;

FIG. 19 depicts the dosage setting member of FIG. 17;

FIG. 20 depicts the dosage setting member of FIG. 17, in a top view;

FIG. 21 depicts a portion of the injection apparatus in accordance withFIG. 3; and

FIG. 22 depicts a portion of the injection apparatus in accordance withFIG. 9.

DETAILED DESCRIPTION

FIG. 1 shows a view of a reservoir part 1 and a mechanism holder 3,which are connected to each other to form the reservoir module 10 shownin FIG. 2.

In FIGS. 1 and 2, a piston rod can be seen which protrudes, on an end ofthe mechanism holder 3 facing away from the reservoir part 1, into themechanism holder 3 and is mounted by the mechanism holder 3 such that itcan shift in an advancing direction pointing in the longitudinal axis Lof the piston rod 4, towards a front end of the reservoir part 1 facingaway from the mechanism holder 3. The reservoir part 1 is substantiallya hollow cylinder which has a circular cross-section and comprises aconnecting region at its front end for connecting to a needle holder foran injection needle. The reservoir part 1 serves to accommodate areservoir container which in the embodiment is formed by an ampoule 2which can be seen in the longitudinal section in FIG. 3. An outlet atthe front end of the ampoule 2 is sealed fluid-tight by a membrane. Whenthe needle holder is fastened to the front end of the reservoir part 1,a rear portion of the injection needle pierces the membrane, such that afluid connection between the tip of the hollow injection needle and thereservoir 2 is established.

FIG. 3 shows the injection apparatus in its entirety, in a longitudinalsection. A piston is accommodated in the ampoule 2 such that it canshift in the advancing direction towards the outlet formed at the frontend of the ampoule 2. Shifting the piston in the advancing directiondisplaces product out of the ampoule 2 and delivers it through theoutlet and the injection needle.

The piston is advanced by the piston rod 4 which pushes against thepiston via its front end and thus moves the piston in the advancingdirection when advanced itself. The piston rod 4 is held by themechanism holder 3 such that it can be moved in the advancing directiononce a certain resistance has been overcome, but not counter to theadvancing direction. The piston rod 4 is prevented from movingbackwards, counter to the advancing direction, by a blocking means 8.The blocking means 8 is axially fixed by the mechanism holder 3, i.e.,it is held in the mechanism holder 3 such that it cannot be moved in andcounter to the advancing direction. It is, however, mounted by themechanism holder 3 such that it can be rotated about the longitudinalaxis L. The blocking means 8 also generates the resistance which has tobe overcome in order to move forwards.

The blocking means 8 is shown on its own in FIG. 6. It is formed by aone-part annular element which, rotatable about the longitudinal axis L,abuts the mechanism holder 3 between two facing, spaced collars 3 bwhich protrude radially inwards from an inner surface of the mechanismholder 3. The collars 3 b form a fixing means for axially fixing theblocking means 8. How the blocking means 8 is mounted in the mechanismholder 3 is most clearly seen from the representation of the mechanismholder 3 in FIG. 5.

Furthermore, a dosage setting member 9 is accommodated in the mechanismholder 3. The dosage setting member 9 is formed as a threaded nut and isin threaded engagement with an outer thread of the piston rod 4. Thedosage setting member 9 is secured against rotating by the mechanismholder 3, but is guided such that it can move axially and linearly inand counter to the advancing direction. The piston rod 4 and the dosagesetting member 9 form a spindle drive for selecting the product dosageto be administered.

The ampoule holder 1 and the mechanism holder 3 are connected to eachother, secured against rotating and shifting, and together form thereservoir module 10 of the injection apparatus, said reservoir module 10comprising the piston rod 4 held by the mechanism holder 3 by means ofthe blocking means 8, and the dosage setting member 9. The ampouleholder 1 and the mechanism holder 3 together form a front casing section1′ of the injection apparatus. A rear casing section 11 is connected tosaid front casing section 1′ in a positive lock. The rear casing section11 forms the support for a dosing and activating element 12 and,together with the dosing and activating element 12 and parts of alatching means and other parts, forms a dosing and activating module 30of the injection apparatus.

Except for the dosage setting member 9, the piston rod 4 and theblocking means 8, a dosing and activating device comprises the othercomponents for selecting the product dosage and activating the injectionapparatus. In particular, it comprises the dosing and activating element12. The dosing and activating device further comprises a counting andindicating means 17 for counting and optically indicating the selectedproduct dosage. Not least, the counting and indicating means 17 makesthe dosing and activating module 30 a high-grade and therefore expensivepart of the injection apparatus. While the comparatively inexpensivereservoir module 10 is designed as a disposable module, the dosing andactivating module 30 is intended for repeated use, with a series of newreservoir modules 10.

For selecting the product dosage or dose, i.e., for dosing, the dosingand activating element 12 can be rotated about the longitudinal axis Land is furthermore mounted by the rear casing section 11 such that itcan linearly shift along the longitudinal axis L, in and counter to theadvancing direction. The dosing and activating element 12 is hollowcylindrical and surrounds the piston rod 4 via a front section. A rearsection of the dosing and activating element 12 protrudes out beyond arear end of the casing section 11. A rod-shaped dosing slaving means 13is inserted into the dosing and activating element 12 from the rear, asfar as a collar of the dosing and activating element 12 protrudingradially inwards. Furthermore, at the rear end, a closure 14 is insertedinto the dosing and activating element 12, as far as the dosing slavingmeans 13. The dosing slaving means 13 is axially fixed relative to thedosing and activating element 12 between the radially protruding collarof the dosing and activating element 12 and the closure 14. The dosingslaving means 13 is also connected, secured against rotating, to thedosing and activating element 12. For the purpose of dosing, the dosingslaving means 13 protrudes into the hollow piston rod 4 from the rear.The piston rod 4 comprises a connecting section 4 a (FIG. 4) whichengages with the dosing slaving means 13 such that the piston rod 4 andthe dosing slaving means 13 and therefore also the dosing and activatingelement 12 cannot be rotated relative to each other about the commonlongitudinal axis L, but can be moved relative to each other along thelongitudinal axis L, in and counter to the advancing direction. For thispurpose, the connecting section 4 a is formed as a linear guide for thedosing slaving means 13.

A restoring means 16 elastically tenses the dosing and activatingelement 12 counter to the advancing direction, into the initial positionshown in FIGS. 3 and 4. In the initial position, the product can bedosed by rotating the dosing and activating element 12 about thelongitudinal axis L. Then, from the initial position, the selectedproduct dosage can be delivered by axially shifting the dosing andactivating element 12. The restoring means 16 is formed by a spiralspring acting as a pressure spring, which is accommodated in an annulargap around the dosing and activating element 12 and axially supportedbetween a collar of the casing section 11 protruding radially inwardsand a collar of the dosing and activating element 12 facing opposite andprotruding radially outwards.

The blocking means 8 fulfils a double function. On the one hand, itensures via its blocking elements 8 a that the piston rod 4 cannot bemoved back, counter to the advancing direction, relative to themechanism holder 3 and therefore in particular relative to the pistonaccommodated in the ampoule 2. In its double function as a brake, theblocking means 8 furthermore prevents the piston rod 4 from movingforwards during the dosing process in which the dosage setting member 9is moved axially, counter to the advancing direction, towards the dosingand activating element 12.

In the initial position shown in FIGS. 3 and 4, before dosing, thedosage setting member 9 abuts against a delivery stopper 3 c (FIG. 5)formed by the mechanism holder 3, in the advancing direction. The pistonrod 4 is in permanent touching contact with the piston. For the purposeof dosing, the dosage setting member 9 is moved away from the deliverystopper 3 c towards the dosing and activating element 12 by the threadedengagement with the piston rod 4 and the linear guide from the mechanismholder 3. This reduces a slight distance between a rear stopper area ofthe dosage setting member 9 and a front stopper area of the dosing andactivating element 12, but on the other hand increases the slightdistance between a front stopper area of the dosage setting member 9 andthe delivery stopper 3 c. The latter distance between the deliverystopper 3 c and the dosage setting member 9 is the path length by whichthe dosage setting member 9 and—due to the threaded engagement—also thepiston rod 4 are moved in the advancing direction in the course of thedelivery movement of the dosing and activating element 12. The deliverystopper 3 c forms a front translational stopper. During the deliverymovement, the piston rod 4 pushes via its front end, which is formed bya plunger body connected to the piston rod 4 such that it cannot move inor counter to the advancing direction, against the piston and pushes thepiston forwards in the advancing direction towards the outlet of theampoule 2. The longitudinal axis L forms the rotational andtranslational axis of the movements which are performed for the purposeof dosing and delivering the product.

The distance which the dosage setting member 9 and the dosing andactivating element 12 exhibit between each other during the dosingprocess when the dosage setting member 9 abuts against the deliverystopper 3 c corresponds to the maximum product dosage which can beselected and delivered in the course of a delivery. The stroke movementof the dosing and activating element 12 is of equal length for eachdelivery. Dosing merely sets the distance between the dosage settingmember 9 and the delivery stopper 3 c and therefore the path lengthwhich can be jointly traveled by the dosing and activating element 12and the dosage setting member 9 in the course of delivery.

The braking function of the blocking means 8 and the braking engagementwhich exists between the piston rod 4 and the blocking means 8 for thispurpose are clear from an overview of FIGS. 6 and 7. On the one hand,the blocking means 8 comprises two braking elements 8 b for the brakingengagement, which are each formed by an elastically flexing catch, likethe blocking elements 8 a before them. In the depicted embodiment, theblocking means 8 is formed by a single annular element from which fourelastic catches axially project on an abutting side. The catches arearranged in a uniform distribution over the circumference of the annularelement. Two mutually opposing catches form the blocking elements 8 aand the other two catches, likewise arranged mutually opposing, form thebraking elements 8 b.

The piston rod 4 accordingly comprises two returning blocking means 6,which are formed on the outer surface on opposing sides and extend inthe longitudinal direction of the piston rod 4, and two advancingbraking means 7, which likewise extend in the longitudinal direction ofthe piston rod 4 on mutually opposing sides. The thread of the pistonrod 4 for the threaded engagement with the dosage setting member 9 isformed by four remaining threaded sections 5 which extend over almostthe entire length of the piston rod 4. The returning blocking means 6and the advancing braking means 7 are each formed by a row of teeth.However, while the teeth of the returning blocking means 6 are formed asserrated teeth, narrowing in the advancing direction and comprisingblocking areas pointing backwards and extending transverse to theadvancing direction, the two rows of teeth which form the advancingbraking means 7 do not comprise blocking areas pointing forwards havinga comparable blocking effect. The teeth of the advancing braking means 7each exhibit a “softer” tooth profile as compared to the returningblocking means 6. For the braking engagement between the blocking means8 and the advancing braking means 7 of the piston rod 4 is not intendedto prevent the piston rod 4 from being advanced, but merely to make itmore difficult, in order to ensure that the piston rod 4 is not moved inthe advancing direction during dosing. The front sides of the teeth ofthe advancing braking means 7 and the rear sides of the braking elements8 b, which touch the front sides of the teeth of the advancing brakingmeans 7, are shaped such that a threshold force which is not reachedduring dosing has to be overcome in order to overcome the brakingengagement. This threshold force is larger than the force required tomove the teeth of the returning blocking means 6 over the blockingelements 8 a in the advancing direction. The threshold force ispreferably at least twice as large as the initial frictional forcebetween the returning blocking means 6 and the blocking elements 8 a.The frictional force between the latter also only increases graduallybetween two consecutive blocking engagements in the course of theadvancing movement. The threshold force of the braking engagement, bycontrast, has to be applied from one blocking engagement to the next,immediately at the beginning of the advancing movement, in each blockingengagement. The threshold force should not, however, be so large that itdistracts the user during delivery.

An undesired advancing movement by the piston rod as a response to themovement by the dosage setting member 9 when selecting the dosage can inprinciple also be prevented by the blocking engagement of the blockingmeans 8 alone. However, such a movement is more reliably preventedbecause of the braking engagement than by the blocking engagement alone.

The connection between the reservoir module 10 and the dosing andactivating module 30 is a positive lock. On the one hand, a latchingengagement exists between the mechanism holder 3 and the casing section11 which prevents relative movement in the axial direction. Beyond thelatching engagement, the front casing section 1′ and the rear casingsection 11 are guided axially and linearly directly onto each other, inorder to prevent relative rotating when connected or connected. Theaxial guides 3 d of the mechanism holder 3, which together with one ormore corresponding engagement elements of the rear casing section 11form the linear guide, can be clearly seen in FIG. 5. The axial guides 3d are formed by guide areas on guide ribs; they could also be formed byguide areas in axially extending recesses. In this way, axial guidechannels are obtained. The guide ribs are axially tapered, such thatinsertion funnels leading into the guide channels are formed for the oneor more engagement elements of the rear casing section 11. In order toeven better center the casing sections 1, 3 and 11 at the beginning ofconnecting, the guide ribs are also tapered in the radial direction. Theone or more engagement elements of the rear casing section 11 is or arepreferably formed like the axial sections 3 d on the surface counterarea, i.e., the inner surface area of the rear casing section 11.

The latching engagement exists between a first, female latching element3 a of the mechanism holder 3 (FIG. 5) and a latching ring 20 which isconnected to the rear casing section 11 such that it can move radiallybut not axially. The latching ring 20 forms a second, male latchingelement 21 which radially engages directly with the first latchingelement 3 a. A lock/latch connection exists between the first latchingelement 3 a and the second latching element 21 which prevents thereservoir module 10 and the dosing and activating module 30 from movingaxially relative to each other.

FIGS. 3 and 4 show the latching element 21 in latching engagement withthe latching element 3 a. The latching element 3 a is formed by anannular stay and a groove which runs around the outer surface of themechanism holder 3. The annular stay forms a rear side wall of thegroove. The second latching element 21 is formed by a cam whichprotrudes radially inwards from the inner surface of the latching ring20 and which in the latching engagement is pushed radially inwards overan inner surface area of the rear casing section 11, protruding into theaccommodating latching element 3 a, by a restoring means 24. Thelatching ring 20 is supported in its entirety in the radial direction onan inner surface area formed by the rear casing section 11, by means ofthe restoring means 24, such that the restoring means 24 pushes againstthe outer surface of the latching ring 20 roughly in a radial extensionof the latching element 21. The latching ring 20 surrounds the mechanismholder 3 and can be moved in its entirety radially back and forthagainst the restoring force of the restoring means 24, such that thesecond latching element 21 can be moved in and out of latchingengagement with the first latching element 3 a. The rear casing section11 forms a tight sliding guide for the radial movement of the latchingring 20. On its side radially opposite the latching element 21, thelatching ring 20 forms an unlatching button 22 for the user. In order toradially guide the restoring means 24 formed as a pressure spring, aguide cam projects radially from the outer surface area of the latchingring 20 facing away from the latching element 21.

Two blocking cams 23, which press radially outwards against a latchingblock 25, furthermore project from the outer surface area of thelatching ring 20, in the circumferential direction on both sides of saidguide cam and axially behind the guide cam. Since the blocking cams 23abut against the latching block 25, a radial movement of the latchingelement 21—which could result in the latching engagement beingreleased—is prevented. The latching engagement between the latchingelements 3 a and 21 is thus secured by the latching block 25. Thelatching engagement is secured in every position of the dosing andactivating element 12, except for a releasing position which the dosingand activating element 12 assumes at the end of its delivery movement.The releasing position therefore coincides with the foremost shiftingposition which the dosing and activating element 12 assumes when itabuts the dosage setting member 9 in the course of its delivery movementand the dosage setting member 9 for its part abuts against the deliverystopper 3 c of the mechanism holder 3. Providing the dosing andactivating module 30 is not yet connected to the reservoir module, amechanical stopper for the dosing and activating element 12 is formed bya stopper element 31 of the dosing and activating device. A reset holderring which serves to reset the indicator 17 forms the stopper element31. The dosing and activating element 12 abutting against said stopperelement 31 defines the releasing position of the dosing and activatingelement 12 in this case, the releasing position defined by the stopperelement 31 corresponding to that defined by the dosage setting member 9abutting the delivery stopper 3 c.

FIG. 8 shows the latching block 25. In the exemplary embodiment, it isformed as one piece by a blocking slider. The latching block 25comprises a plate-shaped main body which extends axially when assembled,as for example shown in FIG. 4. At one end, a stay 26 projects at rightangles from the main body. When assembled, the stay 26 extends radiallyas far as the dosing and activating element 12. The stay 26 serves tofasten the latching block 25 to the dosing and activating element 12which for this purpose comprises two annular stays formed axially spacedon an outer surface area, which form the slaving means 15 a and 15 b.The front slaving means 15 a simultaneously forms the support collar forthe restoring means 16. In the annular space formed between the slavingmeans 15 a and 15 b, the latching block 25 protrudes in via its stay 26and is tightly enclosed axially on both sides by the two slaving means15 a and 15 b.

At a front end facing away from the stay 26, the main body of thelatching block 25 is provided with an axial recess 27 which is opentowards the front end of the latching block 25. In this way, blockingtongues 28 extending axially on both sides of the recess 27 are formed.The blocking cams 23 of the latching ring 20 are arranged such that eachof said blocking cams 23 pushes against one of the blocking tongues 28,providing the dosing and activating element 12 does not assume thereleasing position. When the latching block 25 moves axially, therestoring means 24 for the latching element 21 extends through the axialrecess 27.

Indentation recesses 29 are furthermore formed in the main body of thelatching block 25, and define the releasing position of the dosing andactivating element 12. One indentation recess 29 is provided for each ofthe blocking cams 23. The position of the indentation recesses 29 isselected such that they only overlap the blocking cams 23, and thusallow the blocking cams 23 to be inserted, when the dosing andactivating element 12 has been advanced into its releasing position.

It is clear that in the arrangement specifically selected in theexemplary embodiment, a single blocking cam 23 could also be providedand the latching block 25 accordingly comprise only one indentationrecess 29 and possibly also only one blocking tongue 28. Furthermore,the latching block could in principle be produced together with thedosing and activating element 12 as one piece. Forming it as a separatepart, however, offers advantages with regard to production, assembly andthe dosing and activating element 12 cooperating with the piston rod 4.With respect to the installation length of the latching block 25, itshould also be pointed out that the latching block 25 is supported, onits outer side facing away from the latching element 21, on an innersurface area of the casing 11. In this way, the stability of securingthe latching engagement is increased. The casing 11 preferably forms anaxial guide for the latching block 25.

The functionality of the injection apparatus is described in thefollowing, wherein it is assumed that a new reservoir module 10 and adosing and activating module 30 which has already been used at leastonce are assembled and a product is then delivered for the first time.

The dosing and activating module 30 and the new reservoir module 10 arealigned axially with respect to each other, such that their twolongitudinal axes are flush with each other. The reservoir module 10 isthen inserted via its rear end into the casing 11, which is open to thefront, of the dosing and activating module 30.

This centers the casing section 1′ and the casing section 11 on thetapered ends of the guide ribs 3 d of the mechanism holder 3. Whilebeing slid on, the two casing sections are guided axially and linearlyonto each other in a rotational angular position pre-set by the linearguide, until the casing sections 1′ and 11 assume a connecting endposition in which the latching engagement of the latching elements 3 aand 21 can be established or can be set by itself.

The dosing and activating element 12 is locked in pre-set rotationalangular positions relative to the rear casing section 11. The linearguide of the casing sections 1′ and 11 and the rotational angularlocking positions of the dosing and activating element 12 are adjustedto each other such that the engagement, secured against rotating,between the dosing and activating element 12 and the piston rod 4 isestablished in every locking position of the dosing and activatingelement 12 and every rotational angular position in which the casingsections 1′ and 11 are linearly guided onto each other.

If the dosing and activating element 12 is situated in an axial positionrelative to the casing section 11 which is behind the releasingposition, the latching element 21 is held in its radially innermostposition by the latching block 25. In this position of the latchingelement 21, the dosing and activating module 30 and the reservoir module10 cannot be slid onto each other up to the connecting end position andtherefore also cannot be connected to each other, since the annular stayformed on the outer surface of the mechanism holder 3, which forms apart of the first latching element 3 a, comes to rest abutting againstthe second latching element 21 first.

The annular stay can be reduced to a short radial protrusion in thetangential direction, if it is ensured that the casing sections 1′ and11 can only be assembled in the rotational angular position in whichsuch a protrusion and the second latching element 21 come to rest in anaxial flush. The annular stay or radial protrusion could also form thefirst latching element 3 a alone, since the essential function of thefirst latching element 3 a is to allow the connection between thereservoir module 10 and the dosing and activating module 30 to beestablished only when the dosing and activating element 12 assumes itsreleasing position. If this condition is fulfilled, then the dosing andactivating element 12 would ensure, when the connection between thereservoir module 10 and the dosing and activating module 30 isestablished, that the dosage setting member 9 is situated in its dosingzero position in which it abuts the delivery stopper 3 c of themechanism holder 3.

In order to fulfill the condition described above, the user pushes thedosing and activating element 12 axially forwards relative to the rearcasing section 11 as far as the releasing position. In this relativeposition between the rear casing section 11 and the dosing andactivating element 12, the blocking cams 23 can be moved into theindentation recesses 29 of the latching block 25. The user therefore notonly pushes the dosing and activating element 12 at least as far as thereleasing position, but simultaneously also pushes the second latchingelement 21 out of latching engagement by means of the unlatching button22. The reservoir module 10 can then be moved axially over the annularstay of the first latching element 3 a and inserted further into therear casing section 11. The user can let go of the unlatching button 22.As soon as the second latching element 21 overlaps the first latchingelement 3 a, it snaps into the accommodating latching element 3 a due tothe force of the restoring means 24, such that the latching engagementis established. The reservoir module 10 and the dosing and activatingmodule 30 are then connected to each other in a defined way with respectto the position of the dosage setting member 9 and the piston rod 4. Ifthe dosage setting member 9 still exhibited a slight distance from thedelivery stopper 3 c before the latching engagement is established, thisdistance is eliminated due to the action of the dosing and activatingelement 12, required to establish the connection. A resultant deliveryof product can be accepted and even desired, for the purpose of primingthe injection needle. This preferably resets the counting and indicatingmeans 17 to zero.

In the defined initial state brought about in this way, the user candose the product. The product is dosed by rotating the dosing andactivating element 12 about the longitudinal axis L and relative to thecasing section 11. Since the dosing slaving means 13 is connected to thedosing and activating element 12, secured against rotating, and for itspart engages with the piston rod 4, secured against rotating, the dosingand activating element 12 slaves the piston rod 4 during its rotationaldosing movement. Due to the threaded engagement between the piston rod 4and the dosage setting member 9 and the linear guide of the dosagesetting member 9 by the mechanism holder 3, the dosage setting member 9performs an axial, translational dosing movement, pre-set by the threadpitch of the reciprocal threaded engagement, towards the dosing andactivating element 12. The dosing and activating element 12 forms a reartranslational stopper 12 c which limits the translational dosingmovement of the dosage setting member 9 and thus defines the maximumdelivery stroke which may be set.

The counting and indicating means 17 counts the dosage unitscorresponding to the rotational angular position of the dosing andactivating element 12 and indicates it optically.

Once the desired product dosage has been selected, the dosing process iscompleted. The selected product dosage is delivered by means of thedelivery movement, pointing in the advancing direction of the piston, ofthe dosing and activating element 12. In the course of its deliverymovement, the dosing and activating element 12 abuts against the dosagesetting member 9 and slaves it. When the dosage setting member 9 abutsagainst the delivery stopper 3 c of the mechanism holder 3 in the courseof the delivery movement, the delivery movements of the dosing andactivating element 12 and the delivery of product are completed. Oncethe user lets go of the dosing and activating element 12, it ispreferably moved counter to the advancing direction, back into a newinitial position for dosing and delivering the product again, by therestoring means 16. The counting and indicating means 17 is preferablycoupled to the dosing and activating element 12 such that it has in themeantime been reset back to zero. It possibly possesses means forcounting and indicating the total product amount already delivered andthus the residue product amount remaining in the ampoule 2.

In order to detach the reservoir module 10 from the dosing andactivating module 30, the dosing and activating element 12 is advancedas far as the releasing position, i.e., until it abuts against thedosage setting member 9. in this position, the user can release thelatching engagement again by pushing onto the unlatching button 22, andseparate the reservoir module 10 from the dosing and activating module30.

FIGS. 9 to 13 shows a longitudinal section and four cross-sections of asecond exemplary embodiment of an injection apparatus. The injectionapparatus of the second embodiment is identical to that of the firstembodiment with respect to the latch and latching block 25, such thatreference is made in this regard to the description of the firstembodiment. In particular, the latching block 25 of the secondembodiment is identical to that of the first embodiment with respect toall its functional details. The same applies to the latching elements 3a and 21.

The latching ring 20 and the position of the blocking cams 23 relativeto the latching element 21 and relative to the latching block 25 in theinitial state of the apparatus can be seen particularly clearly in thecross-sections of FIGS. 10, 11 and 12, to which reference is made inthis regard, also as representative for the first embodiment.

The injection apparatus of the second embodiment differs from the firstembodiment in the engagement and the progression of movement of thecomponents involved in dosing. Furthermore, the mechanism holderfulfils, in addition to the functions of the mechanism holder of thefirst embodiment, the function of positioning the dosage setting memberin discrete rotational angular positions which may be changed relativeto the mechanism holder for the purpose of dosing. The blocking means ofthe second embodiment, by contrast, is embodied more simply than that ofthe first embodiment. Primarily, only the differences as compared to thefirst embodiment will be described in the following, wherein forcomponents which are identical in their basic function to the componentsof the same name in the first embodiment but differ in details, numbersin the thirties with the same end digit, or exactly the same referencenumerals as in the first embodiment, as used. Where no statements aremade regarding the second embodiment, the corresponding statementsregarding the first embodiment shall apply.

In the second embodiment, the dosing and activating element 32, whichcan be axially and linearly moved relative to the rear casing section 11and rotated about the longitudinal axis L, is connected to the dosagesetting member 39, secured against rotating. The dosing and activatingelement 32 and the dosage setting member 39 can be moved in and counterto the advancing direction, relative to each other and relative tocasing sections 1′ and 11. The piston rod 4 is held by a mechanismholder 3, secured against rotating. In cooperation with blockingelements of the blocking means 38, formed on the mechanism holder 3 asone piece, the returning blocking means 6, which is functionallyidentical to the first embodiment, prevents the piston rod 4 from movingcounter to the advancing direction, but allows it to move in theadvancing direction. The blocking elements simultaneously form thereturning block and the rotational block for the piston rod 4.Furthermore, as previously in the first embodiment, the dosing andactivating element 32 forms a sliding guide for the piston rod 4.

During dosing, the dosing and activating element 32 performs the samerotational dosing movement as the dosing and activating element 12 ofthe first embodiment. However, since the engagement is secured againstrotating, the dosage setting member 39 is slaved during the rotationaldosing movement. The threaded engagement between the piston rod 4 andthe dosage setting member 39 is again comparable to that of the firstembodiment, such that due to the rotational dosing movement and thethreaded engagement with the piston rod 4, a stopper 39 c formed by thedosage setting member 39 is moved, in the course of dosing, counter tothe advancing direction, towards a front end of the dosing andactivating element 32. As opposed to the first embodiment, the dosagesetting member 39 thus completes a rotational dosing movement and atranslational dosing movement relative to the front casing sectionduring dosing, while the piston rod 4 remains stationary. Once dosinghas been completed, the delivery movement of the dosing and activatingelement 32 advances the piston rod 4 by the path length whichcorresponds to the slight distance between a stopper area of the dosagesetting member 39 and the delivery stopper 3 c of the mechanism holder3, set by the dosing.

The translational dosing movement of the dosage setting member 39 islimited counter to the advancing direction by a rear translationalstopper 11 c which is formed directly by the rear casing section 11itself. In the second embodiment, too, the rotational and translationalaxis of the components involved in dosing and delivering the productforms the longitudinal axis L.

As in the first embodiment, the front casing section 1′ forms a slidingguide for the dosage setting member 39. In order to form the slidingguide, an inner surface area of the mechanism holder 3 and an outersurface area of the dosage setting member 39 are in sliding contact witheach other. The dosing and activating element 32 engages with an innersurface area of the dosage setting member 39, to form the connection,secured against rotating, between the dosage setting member 39 and thedosing and activating element 32.

In the second embodiment, the piston rod 4 comprises no braking means ofits own beyond the returning blocking means 6. Rather, the front sidesof the serrated teeth of the returning blocking means 6 also form thebraking means on their own. The piston rod 4 of the second embodimentcan, however, be replaced by the piston rod 4 of the first embodiment.Accordingly, the mechanism holder 3 of the second embodiment would inthis case also have to form at least one braking element, preferablyboth braking elements, of the first embodiment.

FIGS. 14 to 16 show the mechanism holder 3 of the second embodiment in aperspective representation, a side view and in the cross-section A-Aindicated in the side view. As in the first embodiment, the mechanismholder 3 is embodied as a one-part sleeve part, preferably as a plasticinjection molded part. It comprises a bulge 3 e on the outer surface ofa front sleeve section. The front sleeve section is plugged into thereservoir part 1 and locked non-detachably, at least for the user, tothe reservoir part 1 by means of the bulge 3 e.

The latching element 3 a is formed on a middle sleeve section of themechanism holder 3, as in the first embodiment.

A rear sleeve section, connected to the latching element 3 a, forms aplurality of axial guides 3 d on its outer circumference. The axialguides 3 d are formed by guide ribs which protrude radially on the outercircumference of the rear sleeve section. More precisely, the axialguide formed by the axially extending, straight side walls of said guideribs, such that—as in the first embodiment—axial guiding channels areobtained. The guide ribs protrude out from the middle sleeve sectionlike fingers, as far as the rear end of the mechanism holder 3, wherethey taper off axially. The axial guide 3 d serves to linearly guide therear casing section 11 when the reservoir module 10 is connected to thedosing and activating module 30. As can be seen in FIG. 9 and mostclearly in FIG. 11, engagement elements 11 d project radially inwardsfrom the inner surface area of the rear casing section 11, correspondingin number and adapted in shape. One engagement element 11 d protrudesinto each of the axial guides 3 d and is linearly guided by the axialguide 3 d when the front casing section 1′ and the rear casing section11 are slid into each other in order to be connected. In this way, it isensured that there is no relative rotating between the front casingsection 1′ and the rear casing section 11 when the engagement, securedagainst rotating, between the dosing and activating element 32 and thedosage setting member 39 is established in the course of connecting.

Since the guide ribs taper off axially at their rear ends, and the guidechannels are thus widened into insertion funnels, centering between thefront casing section 1′ and the rear casing section 11, for the purposeof connecting, is made easier. The guide ribs also taper off at theirends radially with respect to the surface area of the mechanism holder3, which makes centering the casing sections 1′ and 11 into a rotationalangular position pre-set by the axial guide 3 d, relative to each other,even easier.

Just as the front casing section 1′ and the rear casing section 11 areprevented from rotating relative to each other when sliding them intoeach other, the dosage setting member 39 is also fixed with respect toits rotational angular position relative to the front casing section 1′,the dosage setting member 39 being detachably fixed in order to allowthe rotational movement of the dosage setting member 39 necessary fordosing. In order therefore to enable the dosing movement of the dosagesetting member 39 on the one hand, but to prevent an undesired dosingmovement by establishing the connection between the front casing section1′ and the rear casing section 11, the dosage setting member 39 is fixedby the mechanism holder 3 in discrete rotational angular positions, bymeans of a releasable locking connection.

FIGS. 17 to 20 show individual representations of the dosage settingmember 39. For forming the locking connection, a number of lockingrecesses 39 g are formed on the outer surface area of the dosage settingmember 39, distributed in regular separation over the circumference.Each of the locking recesses 39 g is formed by a straight, axiallyextending furrow having a rounded contour running in its cross-section.

The mechanism holder 3 is provided with two locking projections 3 g(FIGS. 15 and 16). The two locking projections 3 g project radiallyinwards from an inner surface area of the mechanism holder 3 in the rearsleeve section of the mechanism holder 3. They are arrangeddiametrically opposed to each other. The respective surface region ofthe mechanism holder 3, on which one of the locking projections 3 g isformed, forms a spring element 3 f which is elastically flexible in theradially direction. Due to the elastic flexibility and the rounded shapeof the locking projections 3 g, in conjunction with the rounded profileof the locking recesses 39 g, the locking engagement between the lockingprojections 3 g and the opposing locking recesses 39 g may be released.This is necessary for selecting the dosage. On the other hand, thelocking engagement is however designed such that the dosage settingmember 39 is rotationally angularly fixed sufficiently stable that therecannot be any undesired dosing movement of the dosage setting member 39when the front casing section 1′ and the rear casing section 11 areconnected, when the rotational coupling between the dosing andactivating element 32 and the dosage setting member 39 is established.The locking connection between the mechanism holder 3 and the dosagesetting member 39 has the advantageous side effect of a tactile signalduring dosing. In order to maintain the favorable elasticity of thespring element 3 f, the rear sleeve section of the mechanism holder 3 iscut away in the surface region in question, such that the spring element3 f is maintained as an annular segment extending in the circumferentialdirection which is axially free on both sides.

Axial guides 39 d for the engagement, secured against rotating, betweenthe dosage setting member 39 and the dosing and activating element 32may likewise be seen in FIGS. 17, 18 and 20. The dosing and activatingelement 32 is provided with at least one engagement element, in order toobtain the axial linear guide, i.e., the rotational block, between thedosing and activating element 32 and the dosage setting member 39. Theaxial guides 39 d are again guide channels formed by a number of guideribs extending axially in a straight line. Each of the guide ribs tapersoff axially and radially at its rear end facing the dosing andactivating element 32, in order to make centering between the dosing andactivating element 32 and the dosage setting member 39 easier, when theengagement, secured against rotating, is established. The same design istherefore used for the axial linear guide of the dosage setting member39 and the dosing and activating element 32 as for the axial linearguide of the casing sections 1′ and 11.

For the sake of completeness, reference is lastly also made to thedosing thread 39 a and the delivery stopper 39 c of the dosage settingmember 39, which can most clearly be seen in FIG. 18.

Lastly, two rotational blocks are provided for the dosage setting member39 which are active in the two axial end positions of the dosage settingmember 39. Reference is additionally made in this regard to FIG. 22.

In order to prevent the possibility of the piston rod 4 being moved backin response to a rotational dosing movement by the dosage setting member39, rotational stoppers 39 h are formed at a front end of the dosagesetting member 39. In the front position, which the dosage settingmember 39 assumes directly after the product is delivered or before thedosage is selected, the rotational stoppers 39 h engage with rotationalcounter stoppers 3 h formed on the mechanism holder 3 (FIG. 16). Therotational stoppers 39 h axially project from a front abutting side ofthe dosage setting member 39, and the rotational counter stoppers 3 hprotrude from an axially facing abutting area of the mechanism holder 3forming the delivery stopper 3 c, axially opposed to the rotationalstoppers 39 h. The engagement between the rotational stoppers 39 h andthe rotational counter stoppers 3 h is such that it allows a rotationaldosing movement in a rotational direction, which causes a translationaldosing movement of the dosage setting member 39 directed away from thedelivery stopper 3 c, but prevents a rotational dosing movement in theopposite rotational direction, in the front axial end position.

Furthermore, another pair of rotational stoppers and rotational counterstoppers is provided, which are formed and cooperate in basically thesame way as the stoppers 3 h and 39 h. Said second pair of rotationalstoppers are rotational stoppers 39 i on the one hand, which axiallyproject from a rear abutting area of the dosage setting member 39, androtational counter stoppers 11 i on the other, which axially protrudefrom the facing stopper abutting area of the rear translational stopper11 c towards the dosage setting member 39, which however cannot be seenin FIG. 9 due to their small dimensions. In the rear end position, therear pair of rotational stoppers 11 i/39 i prevents the possibility ofthe piston rod 4 being moved in the advancing direction in response to adosing movement by the dosage setting member 39, directed against therear translational stopper 11 c.

The height, i.e., the axial length, of all the rotational stoppers 3 h,39 h, 11 i and 39 i is adjusted to the thread pitch of the engageddosing thread of the piston rod 4 and the dosage setting member 39. Therotational stoppers are axially sufficiently short that the rotationaldosing movement which moves the dosage setting member 39 away from therespective translational stopper 3 c or 11 c is not impeded.

When assembling the components of the reservoir module 10, the dosagesetting member 39 is screwed onto the piston rod 4 as far as a pre-setaxial position, as may be seen from FIG. 9. The piston rod 4, togetherwith the screwed-on dosage setting member 39, is then inserted into themechanism holder 3 from behind, until its blocking means 38 comes intoblocking engagement with the returning blocking means 6 of the pistonrod 4 and furthermore the engagement, secured against rotating, betweenthe rotational stoppers 39 h of the dosage setting member 39 androtational counter stoppers of the mechanism holder 3 is established.Even while being inserted into the mechanism holder 3, the dosagesetting member 39 is axially and linearly guided by the mechanism holder3 via the locking engagement between the locking projections 3 g and thelocking recesses 39 g, until the dosage setting member 39 abuts thedelivery stopper 3 c of the mechanism holder 3. In this front endposition of the dosage setting member 39 relative to the mechanismholder 3, the engagement, secured against rotating, between therotational stoppers 3 h and 39 h has also already been established.

In this state, the mechanism holder 3 and a reservoir part 1, alreadyfitted with a reservoir, are connected to each other.

In a following step, the rear casing section 11 of the completelyassembled dosing and activating module 30 is slid onto the mechanismholder 3, wherein the mechanism holder 3 and the rear casing section 11can be centered with respect to each other due to the axial guides 3 dand the engagement elements 11 d of the rear casing section 11 and, oncecentered, are axially and linearly guided onto each other due to theguide engagement. In the course of sliding the rear casing section 11onto the mechanism holder 3, the dosing and activating element 32 comesinto engagement, secured against rotating, with the dosage settingmember 39, wherein here too a certain centering is also possible first,using a linear guide corresponding to the axial guides 3 d and theengagement elements 11 d.

The dosing and activating element 32 is in locking engagement with therear casing section in discrete rotational angular locking positions andin the locking engagement, i.e., in the respective rotational angularlocking position, is axially and linearly guided. The rotational angulardifference between two consecutive rotational angular locking positionscorresponds to one dosage unit. The linear guide between the mechanismholder 3 and the rear casing section 11 on the one hand, and thediscrete rotational angular positions of the dosage setting member 39relative to the mechanism holder 3 (locking projections 3 g and lockingrecesses 39 g) and the rotational angular locking positions of thedosing and activating element 32 relative to the rear casing section 11on the other, are adjusted to each other such that the two casingsections 1′ and 11 are always slid linearly over each other in arotational angular position such that the dosage setting member 39 andthe dosing and activating element 32 are also aligned relative to eachother for their engagement, secured against rotating, such that there isno relative rotating between the components involved in dosing while thereservoir module 10 is connected to the dosing and activating module 30.

With respect to the other details of assembling, in particular ofestablishing the latching engagement, and of the functionality oroperation of an injection apparatus in accordance with the secondembodiment, reference is made to the description of first embodiment.

Rotational blocks can also be provided in the injection apparatus inaccordance with the first embodiment, which prevent undesired responsemovements by the piston rod 4 in the two axial end positions of thedosage setting member 9 of the first embodiment. FIG. 21 shows the tworotational blocks, which are formed in the same way as the rotationalblocks of the second embodiment. However, the rotational counterstoppers which in the second embodiment are formed on the casingsections 1′ and 11 are formed in the first embodiment by the blockingmeans 8 on the one hand and the dosing and activating element 12 on theother. Thus, a number of rotational stoppers 8 h are formed on theabutting side of the blocking means 8 axially facing the dosage settingmember 9 and axially protrude towards the dosage setting member 9. Sincethe blocking means 8 is axially and immovably mounted by the frontcasing section 1′ and connected, secured against rotating, to the pistonrod 4, a rotational block for the rotational dosing movement between thepiston rod 4 and the dosage setting member 9 is also obtained, via thefront pair of rotational stoppers 8 h/9 h. The second pair of rotationalstoppers is formed between the dosage setting member 9 and the reartranslational stopper 12 c. As in the second embodiment, a number ofrotational stoppers 12 i protrude axially towards the dosage settingmember 9 from the abutting area of the translational stopper 12 caxially facing the dosage setting member 9. As in the second embodiment,the dosage setting member 9 is provided on its rear side with rotationalstoppers 9 i which in the rear axial end position of the dosage settingmember 9 engage with the rotational stoppers 12 i. In the rear axial endposition of the dosage setting member 9, the rear pair of rotationalstoppers 9 i/ 12 i only allows the rotational dosing movement whichcauses a translational dosing movement of the dosage setting member 9 inthe advancing direction.

In the foregoing description, embodiments of the present invention,including preferred embodiments, have been presented for the purpose ofillustration and description. They are not intended to be exhaustive orto limit the invention to the precise form disclosed. Obviousmodifications or variations are possible in light of the aboveteachings. The embodiments were chosen and described to provide the bestillustration of the principals of the invention and its practicalapplication, and to enable one of ordinary skill in the art to utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. All such modificationsand variations are within the scope of the invention as determined bythe appended claims when interpreted in accordance with the breadth theyare fairly, legally, and equitably entitled.

1. A product dispensing apparatus, comprising a disposable reservoirmodule and a reusable dosing and activating module detachably connectedto said reservoir module, said disposable reservoir module comprising:a) a front casing section of said product dispensing apparatus, whichcomprises a reservoir for a product which can be delivered, a blockingmeans and a first connecting means; b) a piston which is accommodated insaid reservoir such that it can be shifted in an advancing directiontowards a reservoir outlet, in order to deliver product; c) and a pistonrod which comprises a returning blocking means which is in blockingengagement with said blocking means, said blocking engagement preventingsaid piston rod from moving counter to said advancing direction,relative to said front casing section, wherein the piston rod is held bya mechanism holder, secured against rotating; said reusable dosing andactivating module comprising: d) a rear casing section of the productdispensing apparatus, which comprises a second connecting means whichtogether with said first connecting means forms the detachableconnection between the reservoir module and the dosing and activatingmodule; and e) a dosing and drive device, using which a dosing movementfor selecting a product dosage and a delivery movement for deliveringthe product dosage can be performed relative to at least one of thecasing sections; wherein f) the product dispensing apparatus furthercomprises a dosage setting member which is moved in the advancingdirection by the dosing and drive device during said delivery movementand which engages with the piston rod such that it is moved jointly withthe piston rod in the advancing direction and is moved relative to thepiston rod counter to the advancing direction, wherein the reusabledosing and activating module is reusable with a series of new disposablereservoir modules.
 2. The product dispensing apparatus as set forth inclaim 1, wherein said product dispensing apparatus is an injectionapparatus.
 3. The product dispensing apparatus as set forth in claim 1,wherein the first connecting means and the second connecting means forman axial linear guide, to prevent the front casing section and the rearcasing section from rotating relative to each other when the frontcasing section is connected to the rear casing section.
 4. The productdispensing apparatus as set forth in claim 1, wherein the firstconnecting means comprises a first latching element and the secondconnecting means comprises a second latching element and said latchingelements are in latching engagement, in order to axially fix the casingsections onto each other.
 5. The product dispensing apparatus as setforth in claim 4, wherein at least one of the latching elements isconnected, radially movable, to one of the casing sections, against anelasticity force.
 6. The product dispensing apparatus as set forth inclaim 1, wherein said dosage setting member is axially and linearlyguided by one of the casing sections.
 7. The product dispensingapparatus as set forth in claim 1, wherein the dosage setting memberengages, detachably in each case, with one of the casing sections inpre-set rotational angular positions.
 8. The product dispensingapparatus as set forth in claim 7, wherein said dosage setting member,when engaged, is axially and linearly guided.
 9. The product dispensingapparatus as set forth in claim 8, wherein said engagement is a lockingengagement.
 10. The product dispensing apparatus as set forth in claim7, wherein a locking projection and a locking recess, one of which isformed on the dosage setting member and the other on one of the casingsections and which are in locking engagement with each other, can bemoved out of locking engagement against a restoring elasticity force.11. The product dispensing apparatus as set forth in claim 1, whereinthe dosage setting member comprises at least one stopper which in thedosing end position of the dosage setting member is in blockingengagement with one of the casing sections, said blocking engagementpreventing a movement of the dosage setting member which could cause aresponse movement by the piston rod counter to the advancing direction.12. The product dispensing apparatus as set forth in claim 1, whereinthe front casing section forms a delivery stopper for the dosage settingmember, said delivery stopper limiting the delivery movement in theadvancing direction.
 13. The product dispensing apparatus as set forthin claim 1, wherein the dosing and drive device and the dosage settingmember engage with each other, wherein said engagement slaves the dosagesetting member during the dosing movement and allows the dosing anddrive device to move in and counter to the advancing direction relativeto the dosage setting member, wherein the dosage setting member forms astopper for the dosing and drive device against which the dosing anddrive device pushes during its delivery movement, in order to move thedosage setting member in the advancing direction.
 14. The productdispensing apparatus as set forth in claim 1, wherein the dosing anddrive device and the piston rod engage with each other wherein saidengagement slaves the piston rod during the dosing movement but allows adelivery movement of the dosing and drive device relative to the pistonrod.
 15. The product dispensing apparatus as set forth in claim 1,wherein the dosing movement is a rotational movement about alongitudinal axis of the piston rod.
 16. The product dispensingapparatus as set forth in claim 15, wherein the piston rod and thedosage setting member are in threaded engagement with each other. 17.The product dispensing apparatus as set forth in claim 1, wherein thedosage setting member is a component of the reservoir module.
 18. Theproduct dispensing apparatus as set forth in claim 1, wherein the dosagesetting member is coupled to the reservoir module.
 19. The productdispensing apparatus as set forth in claim 1, wherein the dosage settingmember is a component of the dosing and activating module.
 20. A productdispensing apparatus, comprising a disposable reservoir module and areusable dosing and activating module detachably connected to saidreservoir module, said disposable reservoir module comprising: a) afront casing section of said product dispensing apparatus, whichcomprises a reservoir for a product which can be delivered, a blockingmeans and a first connecting means; b) a piston which is accommodated insaid reservoir such that it can be shifted in an advancing directiontowards a reservoir outlet, in order to deliver product; c) and a pistonrod which comprises a returning blocking means which is in blockingengagement with said blocking means, said blocking engagement preventingsaid piston rod from moving counter to said advancing direction,relative to said front casing section; said dosing and activating modulecomprising: d) a rear casing section of the product dispensingapparatus, which comprises a second connecting means which together withsaid first connecting means forms the detachable connection between thedisposable reservoir module and the reusable dosing and activatingmodule; and e) a dosing and drive device, using which a dosing movementfor selecting a product dosage and a delivery movement for deliveringthe product dosage can be performed relative to at least one of thecasing sections; wherein f) the product dispensing apparatus furthercomprises a dosage setting member which is moved in the advancingdirection by the dosing and drive device during said delivery movementand which engages with the piston rod such that it is moved jointly withthe piston rod in the advancing direction and is moved relative to thepiston rod counter to the advancing direction, wherein the dosagesetting member completes a rotational dosing movement and atranslational dosing movement relative to the front casing sectionduring dosing, while the piston rod remains stationary, wherein thereusable dosing and activating module is reusable with a series of newdisposable reservoir modules.
 21. The product dispensing apparatus asset forth in claim 20, wherein said product dispensing apparatus is aninjection apparatus.
 22. The product dispensing apparatus as set forthin claim 20, wherein the first connecting means and the secondconnecting means form an axial linear guide, to prevent the front casingsection and the rear casing section from rotating relative to each otherwhen the front casing section is connected to the rear casing section.23. The product dispensing apparatus as set forth in claim 20, whereinthe first connecting means comprises a first latching element and thesecond connecting means comprises a second latching element and saidlatching elements are in latching engagement, in order to axially fixthe casing sections onto each other.
 24. The product dispensingapparatus as set forth in claim 23, wherein at least one of the latchingelements is connected, radially movable, to one of the casing sections,against an elasticity force.
 25. The product dispensing apparatus as setforth in claim 20, wherein said dosage setting member is axially andlinearly guided by one of the casing sections.
 26. The productdispensing apparatus as set forth in claim 20, wherein the dosagesetting member engages, detachably in each case, with one of the casingsections in pre-set rotational angular positions.
 27. The productdispensing apparatus as set forth in claim 26, wherein said dosagesetting member, when engaged, is axially and linearly guided.
 28. Theproduct dispensing apparatus as set forth in claim 27, wherein saidengagement is a locking engagement.
 29. The product dispensing apparatusas set forth in claim 26, wherein a locking projection and a lockingrecess, one of which is formed on the dosage setting member and theother on one of the casing sections and which are in locking engagementwith each other, can be moved out of locking engagement against arestoring elasticity force.
 30. The product dispensing apparatus as setforth in claim 20, wherein the dosage setting member comprises at leastone stopper which in the dosing end position of the dosage settingmember is in blocking engagement with one of the casing sections, saidblocking engagement preventing a movement of the dosage setting memberwhich could cause a response movement by the piston rod counter to theadvancing direction.
 31. The product dispensing apparatus as set forthin claim 20, wherein the front casing section forms a delivery stopperfor the dosage setting member, said delivery stopper limiting thedelivery movement in the advancing direction.
 32. The product dispensingapparatus as set forth in claim 20, wherein the dosing and drive deviceand the dosage setting member engage with each other, wherein saidengagement slaves the dosage setting member during the dosing movementand allows the dosing and drive device to move in and counter to theadvancing direction relative to the dosage setting member, wherein thedosage setting member forms a stopper for the dosing and drive deviceagainst which the dosing and drive device pushes during its deliverymovement, in order to move the dosage setting member in the advancingdirection.
 33. The product dispensing apparatus as set forth in claim20, wherein the dosing and drive device and the piston rod engage witheach other wherein said engagement slaves the piston rod during thedosing movement but allows a delivery movement of the dosing and drivedevice relative to the piston rod.
 34. The product dispensing apparatusas set forth in claim 20, wherein the dosing movement is a rotationalmovement about a longitudinal axis of the piston rod.
 35. The productdispensing apparatus as set forth in claim 34, wherein the piston rodand the dosage setting member are in threaded engagement with eachother.
 36. The product dispensing apparatus as set forth in claim 20,wherein the dosage setting member is a component of the reservoirmodule.
 37. The product dispensing apparatus as set forth in claim 20,wherein the dosage setting member is coupled to the reservoir module.38. The product dispensing apparatus as set forth in claim 20, whereinthe dosage setting member is a component of the dosing and activatingmodule.